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971.
低温环境起动性能是表征车辆动力性能的一项重要指标。对液力机械传动车辆而言,由于综合传动装置自身技术特点,改善车辆起动性能除应当考虑发动机自身起动阻力外,还应当考虑综合传动装置的起动阻力。在系统分析综合传动装置技术特点和功率流向的基础上,总结了发动机起动过程的主要特征,提出采用稳态试验与动态试验相结合的台架试验方法进行综合传动装置起动扭矩测试。以某高速履带车辆为研究对象,进行了综合传动装置起动扭矩测试。试验结果表明,传动油温的变化和各类油泵的功率消耗是决定综合传动装置起动扭矩大小的关键因素,为改进车辆总体设计和提高车辆起动性能提供了依据。 相似文献
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973.
Yan Guan Dayu Zhou Jin Xu Xiaohua Liu Fei Cao Xianlin Dong Johannes Müller Tony Schenk Uwe Schroeder 《固体物理学:研究快报》2015,9(10):589-593
A wealth of studies have confirmed that the low‐field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro‐mechanism. Recently, HfO2 thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub‐coercive polarization reversal properties were investigated for 10 nm thick Si‐doped HfO2 thin films. The applicability of the Rayleigh law to ultra‐thin ferroelectric films was first confirmed, indicating the existence of a multi‐domain structure. Since the grain size is about 20–30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
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975.
Aiping Xi Zhongxin Xu Fengli Liu Yanli Xu Lijun Yu Jie Liu 《Russian Journal of Physical Chemistry B, Focus on Physics》2015,9(6):946-951
The aim of this present work is to investigate the interaction between doxorubicin and bovine serum albumin (BSA) in simulated physiological conditions by spectroscopic methods to reveal potential toxic effects of the drug. The results reflected that doxorubicin made the fluorescence quenching of BSA through a static quenching procedure. The binding constants at 293, 298, and 303 K were obtained as 2.53 × 105, 8.13 × 104, and 3.59 × 104 M–1, respectively. There may be one binding site of doxorubicin on BSA. The thermodynamic parameters indicated that the interaction between doxorubicin and BSA was driven mainly by hydrogen bonding and electrostatic forces. Synchronous fluorescence spectra and circular dichroism (CD) results showed doxorubicin binding slightly changed the conformation of BSA with secondary structural content changes. Förster resonance energy transfer (FRET) study revealed high possibility of energy transfer with doxorubicin-Trp-212 distance of 3.48 nm. The results of the present study may provide valuable information for studying the distribution, toxicological and pharmacological mechanisms of doxorubicin in vivo. 相似文献
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979.
Haibao?Shao Chunlei?WangEmail author Shuhong?Xu Zhuyuan?Wang Haihong?Yin Yiping?CuiEmail author 《Journal of fluorescence》2015,25(2):305-310
Controllable doping is an effective way of tuning the properties of semiconductor nanocrystals (NCs). In this work, a simple strategy of fast doping Cu ions into ZnSe NCs under ambient conditions was proposed. The principle of doping is based on hydrazine (N2H4) promoted cation exchange reaction. By direct addition of Cu ion stock solution into the preformed ZnSe NCs, Cu doped ZnSe NCs can be obtained. Furthermore, the emission of doped NCs can be tuned by changing the amount of impurity ion addition. The cation exchange reaction is facilitated by three factors: 1) N2H4 addition, 2) fast impurity ions, and 3) partial stabilizer removal. The proposed cation exchange reaction in aqueous solution could be an alternate route for NC doping as well as synthesis of ionic NCs. 相似文献